Iran says it fired missiles at US airbase in Qatar, explosions heard over Doha

Iran's military said on Monday it had carried out a "devastating and powerful" missile attack on the Al Udeid US airbase in Qatar, after explosions were heard across the Qatari capital following Tehran's threat to retaliate for US airstrikes.

Iran had issued threats to retaliate against the United States after US bombers dropped 30,000-pound bunker-busters on Iranian underground nuclear sites at the weekend, joining Israel's air war against Tehran, and President Donald Trump mooted the possibility of the Iranian government being toppled.

Qatar's defence minister, quoted by Al Jazeera TV, said its air defences had intercepted missiles directed at the Al Udeid airbase, the largest US military installation in the Middle East, situated across the Gulf from Iran.

Qatari authorities said there were no casualties in the attack, which it condemned and said it reserved the right to respond.

The attack came shortly after a Western diplomat told Reuters there had been a credible threat to a US military base in the Gulf state following the US airstrikes on Iran.

In addition, the US Ain al-Asad airbase in Iraq had activated its air defence system out of concern of a potential attack, military sources told Reuters.

The White House and the Defence Department are closely monitoring potential threats to the Al Udeid airbase, a senior White House official said in Washington on Monday.

Shortly before, Qatar, a small, wealthy Gulf Arab state, announced it had closed its air space temporarily to ensure the safety of residents and visitors. That followed an advisory from the US embassy in Qatar to Americans to shelter in place, out of what it said was "an abundance of caution".

Two US officials said Washington had assessed that Iran could carry out attacks targeting American forces in the Middle East soon, although the US was still seeking a diplomatic resolution that would see Tehran forgo any reprisal.